Extensible electric cable



R. L. TURNER, JR 3,027,417

EXTENSIBLE ELECTRIC CABLE I Filed June 29, 1959 2 Sheets-Sheet 1 March 27, 1962 March 27, 1962 R. TURNER, JR

' EXTENSIBLE ELECTRIC CABLE 2 Sheets-Sheet 2 Filed June 29, 1959 wrimze 5142M, mwaeikt,

United States Patent G F 3,027,417 EXTENSIBLE ELECTRIC CABLE Ralph L. Turner, Jr., Los Angeles, Calif, assignor t Hughes Aircraft Company, Culver City, Calif, a corporation of Delaware Filed June 29, 1959, Ser. No. 824,129 2 Claims. (Cl. 174-69) The present invention relates generally to a cable assembly for providing electrical interconnection between relatively movable objects and relates more particularly to a flexible ribbon cable arrangement having one or more longitudinally disposed conductors bonded thereto, the ribbon being spirally disposed, whereby to provide flexibility and resilient retraction thereof.

In contemporary electronic unit packaging apparatus, it has become common practice to dispose such apparatus in drawers or other types of movable chassis that are in turn carried by or mounted in a suitable cabinet. Electrical or electronic devices thus packaged in the console structure provided by the drawer and cabinet arrangement may then be serviced or inspected without the necessity for complete disassembly of the cabinet or difficult removal of the chassis. In structures of this type, however, problems have been encountered relative to the necessity for providing electrical current or other electrical connections to the movable element. Thishas previously been accomplished by use of wire harnesses or cable structures of suflicient length to permit removal of the drawer. When the drawer is in a closed position, these cables must necessarily be stored in large areas to the rear of the drawer and protected against damage by other drawers of the console. Cables of this type are necessarily expensive, are heavy, require a considerable amount of space or necessitate the use of supplemental equipment to prevent the cables from interfering with other portions of the equipment and necessitate considerable force to remove the drawers.

The present invention, therefore, provides a means for enabling flexible electrical interconnection along a plurality of electrical paths between a fixed portion of the cabinet and a rearward portion of a movable drawer or the like. This connection is made by means of a flat flexible ribbon cable having a plurality of conductors formed thereon, bonded thereto and provided with an insulating coating. This ribbon cable is spirally formed and connected to suitable plug connectors carried by the cabinet and drawer respectively. Upon removal or extension of the drawer, the ribbon cable will thus extend telescopically and will thereafter retract, when desired.

.While the present cable structure will be described in connection with a drawer and a cabinet, it is to be understood that this arrangement may be employed between any type of movable objects wherein electrical connection is desired therebetween. The particular cable hereof is adapted primarily for linear displacement and, while only a single such cable will be described, it is to be understood that a plurality of such cable arrangements may be disposed laterally across a rear portion of a drawer without departing from the spirit and scope hereof.

It is therefore one important object of the present invention to provide a linear displacement electrical cable arrangement.

It is another object of the invention to provide an electrical cable comprising a spirally Wound ribbon cable including means for securing ends thereof to portions of relatively movable objects.

A further object of the invention is to provide an electrical cable having a plurality of conductors thereon and arranged in a spiral manner to permit linear displacement thereof togetherwith low resistance extension and resilient self retraction.

3,027,417 Patented Mar. 27, 1962 ice Still another object of the invention is to provide a ribbon cable disposed in a spiral manner and telescopically extensible to form an electrical interconnecting structure which occupies a minimum amount of space.

A still further important object of the invention is to provide a linear displacement electrical cable that is simple in construction, reliable and eflicient in use, effective in operation and relatively inexpensive in manufacture.

Other and further important objects of the invention will become apparent from the disclosures in the following detailed specification, appended claims and accom panying drawings, wherein:

FIGURE 1 is a fragmentary sectional view of a portion of a cabinet and drawer arrangement showing the present linear displacement electrical cable in a retracted position;

FIG. 2 is an enlarged fragmentary view, partially in section, showing the present electrical cable in an extended position together with means for attaching one end thereof to a plug connector;

FIG. 3 is a fragmentary sectional view showing a manner of attaching another end of the cable to a fixed structure;

FIG. 4 is a fragmentary sectional view, taken substantially as indicated by line 4-4, FIG. 3;

FIG. 5 isa longitudinal elevational view showing a fragmentary portion of another form of the invention, and J FIG. 6 is a plan view showing the ribbon cable employed in the form of the invention of FIG.5 and disposed in an opened out position.

With reference to the drawings, and with reference primarily to FIG. 1, the present linear displacement electrical cable is shown as indicated generally at 10. The cable 10 is shown in conjunction with a cabinet 11 having a plurality of drawers 12. The drawers 12 are adapted to contain suitable electrical or electronic equipment and may be withdrawn from the cabinet 11 for service or repair to this equipment. A plurality of electrical harness cables 13 extend into the cabinet 11 and through suitable openings 14 in a rear wall 15 thereof. A rear wall 16 of the drawer 12 is adapted to carry a plug 17.

In practice, the electrical cable unit 10 may be used in multiples thereof and spaced either laterally or vertically across the rear wall 16 of the drawers 12. Also, the use of the linear displacement cables 10 is not to be limited to drawer and cabinet structures but may be employed with any relatively movable objects between which it is desired to maintain electrical interconnection.

As shown primarily in FIGS. 2 and 3, the linear displacement electrical cable structure 10 includes an elongated ribbon cable 18 that may be formed from any suitable flexible material such as, for example, that commercially known as nylon or polytetrafluorethylene, sold under the trademark Teflon by E. I. du Pont de Nemours and Co. or the like and has a plurality of conductors 19 formed thereon and bonded thereto as by a process employed in the manufacture of printed circuits and the like. The cable material is non-conductive with the conductors 19 being either embedded therein or covered with a suitable insulating material. The conductors 19 may be made from copper or the like and are permanently secured to the material of the cable. The conductors 19 also have rounded terminal portions 20 through which suitable openings are formed, surface areas of the terminal portions 20 being exposed for a purpose to be hereinafter more fully described.

It is to be noted that the ribbon cable 18 is formed in a spiral manner, whereby to permit telescopic extension thereof. The cable 18 may be preformed into the detherein when telescopically extended.

As shown primarily in FIG, 2, the plug 17 is disposed through a suitable opening 21 in the rear wall 16 of the drawer 12. The plug 17 has suitable protruding connector tabs 22 to which the electrical material in the drawer 12 may be attached. A second plus 23 is positioned in contact with the plug 1'7 and has suitable pins 24 which mate with connectors 25 in the plug 17. The pins 24 extend through the plug 23 and outwardly therefrom as at 26, with the openings in the terminal portions 20 in the conductors 19 being adapted for disposition over the portions 26. The terminal portions 20 may thereafter be soldered or otherwise fixed to the pin portions 26. The plugs 17 and 23, together with an angle bracket 27 are secured to the end wall 16 by means of bolts 28 and nuts 30.

As shown in FIG. 2, the ribbon cable 18 extends at right angles from the plug 23 and is angularly folded as at 31 for disposition in a direction parallel to a longitudinal portion of the plug 23. The end of the cable 18 and the fold 31 are positioned on a planar surface of the bracket 27,'there being a cover plate 32 which acts as a clamp member to retain the cable and the folded portion thereof in position and which overlies the planar surface of the'braeket 27. The plate member 32 is secured to the bracket 27 by means of suitable bolts 33. The cable 18 is thus retained in position and, upon extension thereof, no force is applied to the pins 26.

As shown primarily in FIG. 3, another end of the cable 18 is secured to a fitting or plug 34, as by connection of terminal ends 35 of the conductors 19 to pins 36. The pins 36 extend above a surface of a fitting 34 and into a longitudinal cavity 37 therein. Individual wires 38 from the'cable 13 are adapted to extend into the cavity 37 for individual connection with the pins 36. The fitting 34 is secured to the rear wall 15 of the cabinet 11 as by an angle bracket 40 that is connected to the fitting as by screws 41 and to the rear wall as by suitable attachment members 42.

It may thus be seen that the flexible ribbon cable 18 is spirally disposed and rigidly connected at each end thereof. Thus, when the drawer 12 or other movable object is displaced from the rear wall 15 of the cabinet 11, the cable 18 will extend in the manner shown in FIGS. 2 and 3, whereby to permit continued electrical connection of a plurality of conductors between these relatively movable objects. With the conductors 19 being contained in the material of the flexible cable 18 or covered with a suitable insulating material, there is no contact or electrical connection between concentrically overlying conductors. When the drawer or other object is returned to its original position, the flexible ribbon cable 18 will again assume is original configuration as shown in FIG. 1. i

As shown in FIGS. and 6, a modified form of the invention includes a ribbon cable 18' having conductors 19 thereon. In this form of the invention, the ribbon cable 18 is adapted for connection with a cylindrical plug 59, with the plug 50 being adapted to mate with another plug 51 carried by a rear wall 16 of a drawer 12'; The cable 18' has a pair of laterally disposed integral tabs 52 and an integral circular portion 53 from which another tab 54 depends. The conductors -19 terminate in laterally extending portions 55 and enlarged terminal: ends 56 that are arranged in a circular pattern and adapted for connection with pins 57 carried by the plug 50. The terminal portions 56 may be soldered or otherwise connected tothepins 57. The tab 54 is fitted with a male snap member 58 that is adapted to extend through an opening 60 in one of the tabs 52 and into a female snap member 61 carried by the other of the tabs 52. Additionally, a second male snap member 62 is carried by one of the tabs 52 and adapted to mate with a female snap member 63 also carried by the other of the tab members 52, whereby to retain an end portion of the cable 18 in the configuration shown in FIG. 5. The modified form of the invention shown in FIGS. 5 and 6 is adapted particularly for use with cable arrangements wherein a reduced number of conductors 19' are required.

It may thus be seen that the linear displacement electrical cable of this invention provides a reliable, efiieient and inexpensive means for enabling a plurality of electrical connections between relatively movable objects and that the spiral configuration thereof provides for retraction and storage of the cable and prevents interference between the cable and any drawers, guides or adjacent elements of an electrical console. Additionally, thepres ent cable may be disconnected from the drawer 12, if desired, and may be replaced with ease, if necessary.

Having thus described the invention and the present embodiments thereof, it is desired to emphasizethe fact that many further modifications may be resorted to in a manner limited only by a just interpretation of the following claims.

I claim:

1. An extensible and rectractable electrical cable for electrically connecting two bodies relatively movable along a substantially linear translatory axis comprisingi a section of elongated, wide,.thin, fiat, flexible ribbon cable, the width of said cable being large compared to the thickness thereof, said cable being loosely coiled upon itself about an axis transverse to the largest dimension of said cable to form a plurality of complete overlapping turns arranged in a spiral, cylindrical configura-v tion, said cable having each of its ends afiixed to a different one of said relatively'movable bodies, the axis of said coiled cable being substantially parallel to the translatory axis between said bodies, the minimum distance between said relatively movable bodies along said translatory axis being at least greater than the width of said cable, the maximum distance between said relatively movable bodies along said translatory axis being no greater than the combined widths of the overlapping turns of said cable, relative movement of said bodies away from each other alongsaid translatory axis causing relative axial displacement of the turns of said coiled cable to form a partially overlapping, self-supporting spiral configuration, the outer surfaces of said cable having a low coefiicient of friction so that little force is necessary to extend and retract said cable, said cable having a plurality of longitudinally disposed, laterally spaced, electrical conductors therein, each of said conductors being provided with enlarged ter-. minal end portions, said end portions being free of insulation, a plug connector having connector pins, said terminal end portions on one end of said conductors being soldered to said pins, a plate clamp secured to said plug connector and disposed in contact with opposite flat sides of said cable, said cable being angularly folded within the confines of said clamp, said plug connector being adapted for connection with elements of one of said movable bodies, and a fitting disposed axially within said coiled cable and adapted for attachment to the other of said movable bodies, said fitting having connection means, said terminal end portions on the other end of 'said conductors being soldered to said connection means.

2. An extensible and retractableelectrical cable for electrically connecting two bodies relatively movable along a substantially linear translatory axis comprising: a section of elongated, wide, thin, fiat, flexible ribbon cable, the width of said cable being largecompared to the thickness thereof, said cable being loosely coiled upon itself about an axis transverse to the largest dimension of said cable to form a plurality of complete overlapping turns arranged in a spiral, cylindrical configuration, said cable having each of its ends afiixed to a different one of said relatively movable bodies, the axis of said coiled cable being substantially parallel to the translatory axis between said bodies, the minimum distance between said I! a relatively movable bodies along said translatory axis being at least greater than the width of said cable, the maximum distance between said relatively movable bodies along said translatory axis being no greater than the combined widths of the overlapping turns of said cable, relative movement of said bodies away from each other along said translatory axis causing relative axial displacement of the turns of said coiled cable to form a partially overlapping, self-supporting spiral configuration, the outer surfaces of said cable having a low coeflicient of friction so that little force is necessary to extend and retract said cable, said cable having a plurality of longitudinally disposed, laterally spaced electrical conductors therein, said conductors having enlarged terminal end portions, said end portions being free of insulation, an annular tab formed integrally on saidcable, said conductors extending onto said tab, snap means disposed on said cable for securing said tab in a position normal to the axis of said coiled cable, an annular plug connector having connector pins, said terminal end portions of said conductors on said tab being soldered to said pins, said plug connector References Cited in the file of this patent UNITED STATES PATENTS 2,015,295 Steingruber Sept. 24, 1935 2,060,913 Weaver Nov. 17, 1936 2,754,488 Horn July 10, 1956 2,854,502 Richter Sept. 30, 1958 2,953,765 Greasley Sept. 20, 1960 OTHER REFERENCES Publication 1: Flexible Cables for Printed Circuits, published in Electronics, Dec. 1955 (page 313 relied on). Publication II: Cable in Tape Form, published in 20 Electronics Design, Aug. 15, 1957 (pages 48 and 49 relied on). 

